The present invention relates generally to the field of information processing by digital computers and, more particularly, to the processing and presentation of information by program applications, particularly electronic spreadsheets.
Before computers, numerical analyses, particularly financial ones, were usually prepared on an accountant's columnar pad or spreadsheet, with pencil and calculator in hand. By organizing data into columns and rows, spreadsheets afford the rapid assimilation of information by a reader. The task of preparing a spreadsheet on paper, however, is not quite so fast. Instead, the process tends to be very slow, as each entry must be tediously calculated and entered into the spreadsheet. Since all calculations are the responsibility of the preparer, manually prepared spreadsheets are also prone to errors. Hence, preparation of spreadsheets by hand is slow, tedious, and unreliable.
With the advent of microcomputers, a solution was forthcoming in the form of "electronic spreadsheets." Better known simply as "spreadsheets," these software programs provide a computerized replacement for the traditional financial modeling tools: the accountant's columnar pad, pencil, and calculator. In some regards, spreadsheet programs are to those tools what wordprocessors are to typewriters. Spreadsheets offer dramatic improvements in ease of creating, editing, and using financial models.
A typical spreadsheet program configures the memory of a computer to resemble the column/row or grid format of an accountant's columnar pad, thus providing a visible calculator for a user. Because this "pad" exists dynamically in the computer's memory, however, it differs from paper pads in several important ways. Locations in the electronic spreadsheet, for example, must be communicated to the computer in a format which it can understand. A common scheme for accomplishing this is to assign a number to each row in a spreadsheet, and a letter to each column. To reference a location at column A and row 1 (i.e., the upper-lefthand corner), for example, the user types in "A1". In this manner, the spreadsheet defines an addressable storage location or "cell" at each intersection of a row with a column.
Data entry into an electronic spreadsheet occurs in much the same manner that information would be entered on an accountant's pad. After a screen cursor is positioned at a desired location, the user can enter alphanumeric information. Besides holding text and numeric information, however, spreadsheet cells can store special instructions or "formulas" specifying calculations to be performed on the numbers stored in spreadsheet cells. In this fashion, cell references can serve as variables in an equation, thereby allowing precise mathematical relationships to be defined between cells. The structure and operation of a spreadsheet program, including advanced functions such as functions and macros, are documented in the technical, trade, and patent literature. For an overview, see e.g., Cobb, S., Using Quattro Pro 2, Borland-Osborne/McGraw-Hill, 1990; and LeBlond, G. and Cobb, D., Using 1-2-3, Que Corp., 1985. The disclosures of each of the foregoing references are hereby incorporated by reference.
Electronic spreadsheets offer many advantages over their paper counterparts. For one, electronic spreadsheets are much larger (i.e., hold more information) than their paper counterparts; electronic spreadsheets having thousands or even millions of cells are not uncommon. Spreadsheet programs also allow users to perform "what if" scenarios. After a set of mathematical relationships has been entered into a worksheet, the spread of information can be recalculated using different sets of assumptions, with the results of each recalculation appearing almost instantaneously. Performing this operation manually, with paper and pencil, would require recalculating every relationship in the model with each change made.
While electronic spreadsheets offer significant productivity gains in the task of complex data modeling, none has been as intuitive to use as ordinary paper and pencil--objects already familiar to the user. Instead, the user must master many complex and arbitrary operations. To find the proper command for a task at hand, for example, the user must hunt through a complex menuing system, with the desired choice often buried under several menus. Even simple tasks can pose a significant challenge to the user. To change the punctuation format of a number in one prior art spreadsheet, for example, the user must traverse several nodes of a menu tree, carefully selecting among cryptic menu choices along the way. A mistake at any one of the nodes can lead to harsh consequences, including the loss of valuable data.
Finding this approach to be unworkable, many users memorize frequently-needed commands instead. To accomplish the foregoing task, for example, the user would memorize the command: /Worksheet Global Default Other International. As one can only memorize just so many arbitrary commands, however, the user typically masters only a very small subset of available commands and features. And without constant practice, these commands tend to be quickly forgotten. Moreover, many useful and needed commands are sufficiently hidden in layers of menus that they are never discovered by the user. All told, the non-intuitive interfaces of prior art spreadsheets have led to steep learning curves for users. Even after mastering a particular spreadsheet interface, the user typically only knows a fraction of available commands and features, most of which are easily forgotten.
Even with advances in computer and software technology, electronic spreadsheets have not necessarily become easier to use. Instead, technological advances have been largely employed to build more complex functions and modeling features into spreadsheets, often with more complicated menu trees; or worse yet, a staggering array of icons which leave the user even more bewildered. Thus, while prior art spreadsheets have continued to increase in functionality, they have also greatly increased in complexity for the user.
Three dimensionality is one such example. Three-dimensional spreadsheets allow the user to create a worksheet having cells arranged in a 3-D grid. In this manner, the user can manipulate multi-dimensional ranges, i.e., solid blocks of cells. This feature has distinct advantages. For example, the user can build a worksheet consisting of multiple two-dimensional spreads, define 3-D ranges that span these spreads, and copy a range of rows and columns into each of many 2-D spreads at once. This feature eases difficult choirs, such as consolidation of multiple spreads.
Despite its advantages, three-dimensionality, as presently implemented, is an advanced feature beyond the grasp of many spreadsheet users. This is not a necessary result of a three-dimensional model per se but, instead, has resulted from poor implementations of the model in prior art spreadsheet programs. One popular implementation of the model in the prior art, for example, requires the user to manipulate each additional spread of a three-dimensional spreadsheet as a separate window in a graphical windowing environment. This approach is far from intuitive, however. In particular, this approach requires the user to master actions which have no counterpart in everyday activities. While three-dimensional spreadsheets provide additional functionality, they serve to illustrate how non-intuitive implementations of new technology greatly add to the complexity of the user interface.
What is needed is application software which maintains a highly intuitive interface. Moreover, the application should implement advanced features, such as three dimensionality, by employing interface objects which are familiar to the user. In this manner, the user will not have to master an elaborate and/or awkward environment but, instead, may rely upon his or her own common fund of knowledge. The present invention fulfills this and other needs.